class A:
    def __init__(self):
        print("A")


class B(A):
    def __init__(self):
        print("B")
        super().__init__()



class C(A):
    def __init__(self):
        print("C")
        super().__init__()



class D(B, C):
    def __init__(self):
        print("D")
        super().__init__()


if __name__ == '__main__':
    test = D()
    print(D.__mro__)
    # print(test)
